Fixing a bowing ceiling

My mom employed a neighborhood handyman to fix her roof. This was a very bad idea. It rained really hard one day and water started dripping down the ceiling.

I managed to located a decent roofer who examined the roof and said it was in bad shape, but nothing was rotten. He fixed the roof and replaced all of the gutter, but the ceiling is still messed up. I have enclosed attachments for the damaged part of the ceiling and the healthy part (ignore the flaking wallpaper, that is another project).

Basically, the ceiling is bowing heavily in one large area, compared to the undamaged section. What should I do to repair it? I never did dry wall, but did some research. The dry walls are panels that are attached to the wooden beams. What's involved with this sort of repair, do I rip out a section of the panel and then nail on a new set of dry wall panels, then fill any gap with putty or something? Is there some possibility that the bowing is from a warped beam? How do I check and get rid of mold if there is any?

Thanks.

Paul

Attached Files:

Once plaster in sheet rock gets wet, it is ruined, and there is no way to patch it or save it. For someone who has never worked with drywall, a ceiling is a very difficult place to begin. First the old ceiling has to be removed. Dirty and ugly job at best. Then new drywall sheets have to be installed. Darned hard work over your head. Then it has to be taped and sanded. Messy, especially for a novice. This may very well be a job for a professional drywaller. They can get the job done quickly and with a minimum of mess.

Edit:
If there is a heavy plastic vapor barrier it might be possible to cut slivers out and put up temporary strips and then replace small sections of sheetrock... However this would be tricky and not something I would try.

I also have first hand experience with dealing with collapsing ceilings and all the insulation dust and all I can say is that it would be easier to strip the ceiling and then add a second layer of Sheetrock.

Dry wall is one material that does recover after it gets wet, but if it has sagged, it hardens to that configuration. If the sag is just the drywall, and not the wood framing, you might be able to pull it back into place by using drywall screws, working from the outer edges towards the center, otherwise cut it out and install a new piece.

I dealed with the exact same problem last year in my house. The problem was on the second floor, and the ceiling had almost no load on top, so the beams that were used had a small cross section, which caused the sagging.

What we ended up doing was making a hole of about 8"x8" to allow for clear access on top of the finished ceiling (crawl space). Once we verified that the beams were component that were causing the sagging, we knew what to do. I used a car jack and vertical plank to jack the ceiling back up to the original height. Then I used a slotted steel angle to keep the ceiling in position, drilling both beams on top/bottom of the crawl space into the angle. Once I removed the car jack, the ceiling did drop slightly, but no where near what it was before. This whole ordeal was caused by a leaking roof.